Sorry to hear about the issue. I have some questions that I hope you can answer. Does it happen even if you save a game right at the beginning of a game (before you have done any action with the character) and then try to load it? When you save the game with Shift+S, does it say in the game log (on the main game screen) that the game is saved? And is there a file Game.save in the Save folder after you saved the game? If you can send the save file to me (for the latest version of the game), I can check if it works for me. It seems that itch.io allows links to files to be added to a message but you can also send the save file to my e-mail address (cwulnil@gmail.com). If all of that fails, it would be nice for me to know the size of the save file.
I managed to track down the bug thanks to your save. I have uploaded a new version (with your name in the credits) and hopefully saving/loading works now. If there are still issues, it would be great if you could send another save file. Unfortunately, your old save file that you sent will not work with the new fix but hopefully there will be no more crashes.